Exemplary embodiments of the present invention relate to semiconductor devices, and more particularly, to a fuse circuit for storing data such as repair information in a semiconductor device.
In general, data of a fuse is classified according to whether a fuse is cut by a laser. Generally, a fuse is programmed in a wafer state, before the wafer is mounted in a package.
An antifuse is used to overcome such a limitation. The antifuse uses a transistor to store data. And data of an antifuse is classified according to the resistance between a gate and a drain/source.
FIG. 1 illustrates an antifuse including a transistor and an operation of the antifuse as a resistor or a capacitor.
Referring to FIG. 1, an antifuse includes a transistor T that has a gate G to which a power supply voltage is applied and a drain/source terminal D/S to which a ground voltage is applied.
When a normal power supply voltage, tolerable by the transistor T, is applied to the gate G, the antifuse operates as a capacitor C. Accordingly, no current flows between the gate G and the drain/source terminal D/S. However, when a high power supply voltage, intolerable by the transistor T, is applied to the gate G, the gate oxide of the transistor T is broken to short the gate G and the drain/source terminal D/S, and therefore, the antifuse operates as a resistor R. Accordingly, a current flows between the gate G and the drain/source terminal D/S.
Based on this fact, data of the antifuse are detected through the resistance value between the gate G and the drain/source terminal D/S. In one method, the data of the antifuse may be detected directly without a sensing operation by increasing the size of the transistor T. In another method, the data of the antifuse may be detected by sensing a current flowing through the transistor T by means of an amplifier, instead of increasing the size of the transistor T. However, the above two methods are disadvantageous in terms of area because the transistor T of the antifuse is designed to have a large size or an amplifier for each antifuse must be included.